com.google.zxing.ChecksumException Java Examples

/**
 * <p>Given data and error-correction codewords received, possibly corrupted by errors, attempts to
 * correct the errors in-place using Reed-Solomon error correction.</p>
 *
 * @param codewordBytes data and error correction codewords
 * @param numDataCodewords number of codewords that are data bytes
 * @throws ChecksumException if error correction fails
 */
private void correctErrors(byte[] codewordBytes, int numDataCodewords) throws ChecksumException {
  int numCodewords = codewordBytes.length;
  // First read into an array of ints
  int[] codewordsInts = new int[numCodewords];
  for (int i = 0; i < numCodewords; i++) {
    codewordsInts[i] = codewordBytes[i] & 0xFF;
  }
  try {
    rsDecoder.decode(codewordsInts, codewordBytes.length - numDataCodewords);
  } catch (ReedSolomonException ignored) {
    throw ChecksumException.getChecksumInstance();
  }
  // Copy back into array of bytes -- only need to worry about the bytes that were data
  // We don't care about errors in the error-correction codewords
  for (int i = 0; i < numDataCodewords; i++) {
    codewordBytes[i] = (byte) codewordsInts[i];
  }
}
 

/**
 * <p>Given data and error-correction codewords received, possibly corrupted by errors, attempts to
 * correct the errors in-place using Reed-Solomon error correction.</p>
 *
 * @param codewordBytes data and error correction codewords
 * @param numDataCodewords number of codewords that are data bytes
 * @throws ChecksumException if error correction fails
 */
private void correctErrors(byte[] codewordBytes, int numDataCodewords) throws ChecksumException {
  int numCodewords = codewordBytes.length;
  // First read into an array of ints
  int[] codewordsInts = new int[numCodewords];
  for (int i = 0; i < numCodewords; i++) {
    codewordsInts[i] = codewordBytes[i] & 0xFF;
  }
  int numECCodewords = codewordBytes.length - numDataCodewords;
  try {
    rsDecoder.decode(codewordsInts, numECCodewords);
  } catch (ReedSolomonException ignored) {
    throw ChecksumException.getChecksumInstance();
  }
  // Copy back into array of bytes -- only need to worry about the bytes that were data
  // We don't care about errors in the error-correction codewords
  for (int i = 0; i < numDataCodewords; i++) {
    codewordBytes[i] = (byte) codewordsInts[i];
  }
}
 

private static DecoderResult decodeCodewords(int[] codewords, int ecLevel, int[] erasures) throws FormatException,
    ChecksumException {
  if (codewords.length == 0) {
    throw FormatException.getFormatInstance();
  }

  int numECCodewords = 1 << (ecLevel + 1);
  int correctedErrorsCount = correctErrors(codewords, erasures, numECCodewords);
  verifyCodewordCount(codewords, numECCodewords);

  // Decode the codewords
  DecoderResult decoderResult = DecodedBitStreamParser.decode(codewords, String.valueOf(ecLevel));
  decoderResult.setErrorsCorrected(correctedErrorsCount);
  decoderResult.setErasures(erasures.length);
  return decoderResult;
}
 

/**
 * <p>Given data and error-correction codewords received, possibly corrupted by errors, attempts to
 * correct the errors in-place using Reed-Solomon error correction.</p>
 *
 * @param codewordBytes data and error correction codewords
 * @param numDataCodewords number of codewords that are data bytes
 * @throws ChecksumException if error correction fails
 */
private void correctErrors(byte[] codewordBytes, int numDataCodewords) throws ChecksumException {
  int numCodewords = codewordBytes.length;
  // First read into an array of ints
  int[] codewordsInts = new int[numCodewords];
  for (int i = 0; i < numCodewords; i++) {
    codewordsInts[i] = codewordBytes[i] & 0xFF;
  }
  int numECCodewords = codewordBytes.length - numDataCodewords;
  try {
    rsDecoder.decode(codewordsInts, numECCodewords);
  } catch (ReedSolomonException ignored) {
    throw ChecksumException.getChecksumInstance();
  }
  // Copy back into array of bytes -- only need to worry about the bytes that were data
  // We don't care about errors in the error-correction codewords
  for (int i = 0; i < numDataCodewords; i++) {
    codewordBytes[i] = (byte) codewordsInts[i];
  }
}
 

@Override
public Result decode(BinaryBitmap image, Map<DecodeHintType,?> hints)
    throws NotFoundException, ChecksumException, FormatException {
  DecoderResult decoderResult;
  if (hints != null && hints.containsKey(DecodeHintType.PURE_BARCODE)) {
    BitMatrix bits = extractPureBits(image.getBlackMatrix());
    decoderResult = decoder.decode(bits, hints);
  } else {
    throw NotFoundException.getNotFoundInstance();
  }

  ResultPoint[] points = NO_POINTS;
  Result result = new Result(decoderResult.getText(), decoderResult.getRawBytes(), points, BarcodeFormat.MAXICODE);

  String ecLevel = decoderResult.getECLevel();
  if (ecLevel != null) {
    result.putMetadata(ResultMetadataType.ERROR_CORRECTION_LEVEL, ecLevel);
  }
  return result;
}
 

@Override
public Result decode(BinaryBitmap image, Map<DecodeHintType,?> hints)
    throws NotFoundException, ChecksumException, FormatException {
  DecoderResult decoderResult;
  ResultPoint[] points;
  if (hints != null && hints.containsKey(DecodeHintType.PURE_BARCODE)) {
    BitMatrix bits = extractPureBits(image.getBlackMatrix());
    decoderResult = decoder.decode(bits);
    points = NO_POINTS;
  } else {
    DetectorResult detectorResult = new Detector(image.getBlackMatrix()).detect();
    decoderResult = decoder.decode(detectorResult.getBits());
    points = detectorResult.getPoints();
  }
  Result result = new Result(decoderResult.getText(), decoderResult.getRawBytes(), points,
      BarcodeFormat.DATA_MATRIX);
  List<byte[]> byteSegments = decoderResult.getByteSegments();
  if (byteSegments != null) {
    result.putMetadata(ResultMetadataType.BYTE_SEGMENTS, byteSegments);
  }
  String ecLevel = decoderResult.getECLevel();
  if (ecLevel != null) {
    result.putMetadata(ResultMetadataType.ERROR_CORRECTION_LEVEL, ecLevel);
  }
  return result;
}
 

@Override
public Result decode(BinaryBitmap image, Map<DecodeHintType,?> hints)
    throws NotFoundException, ChecksumException, FormatException {
  DecoderResult decoderResult;
  ResultPoint[] points;
  if (hints != null && hints.containsKey(DecodeHintType.PURE_BARCODE)) {
    BitMatrix bits = extractPureBits(image.getBlackMatrix());
    decoderResult = decoder.decode(bits);
    points = NO_POINTS;
  } else {
    DetectorResult detectorResult = new Detector(image.getBlackMatrix()).detect();
    decoderResult = decoder.decode(detectorResult.getBits());
    points = detectorResult.getPoints();
  }
  Result result = new Result(decoderResult.getText(), decoderResult.getRawBytes(), points,
      BarcodeFormat.DATA_MATRIX);
  List<byte[]> byteSegments = decoderResult.getByteSegments();
  if (byteSegments != null) {
    result.putMetadata(ResultMetadataType.BYTE_SEGMENTS, byteSegments);
  }
  String ecLevel = decoderResult.getECLevel();
  if (ecLevel != null) {
    result.putMetadata(ResultMetadataType.ERROR_CORRECTION_LEVEL, ecLevel);
  }
  return result;
}
 

/**
 * <p>Given data and error-correction codewords received, possibly corrupted by errors, attempts to
 * correct the errors in-place using Reed-Solomon error correction.</p>
 *
 * @param codewordBytes data and error correction codewords
 * @param numDataCodewords number of codewords that are data bytes
 * @throws ChecksumException if error correction fails
 */
private void correctErrors(byte[] codewordBytes, int numDataCodewords) throws ChecksumException {
  int numCodewords = codewordBytes.length;
  // First read into an array of ints
  int[] codewordsInts = new int[numCodewords];
  for (int i = 0; i < numCodewords; i++) {
    codewordsInts[i] = codewordBytes[i] & 0xFF;
  }
  int numECCodewords = codewordBytes.length - numDataCodewords;
  try {
    rsDecoder.decode(codewordsInts, numECCodewords);
  } catch (ReedSolomonException ignored) {
    throw ChecksumException.getChecksumInstance();
  }
  // Copy back into array of bytes -- only need to worry about the bytes that were data
  // We don't care about errors in the error-correction codewords
  for (int i = 0; i < numDataCodewords; i++) {
    codewordBytes[i] = (byte) codewordsInts[i];
  }
}
 

/**
 * <p>Given data and error-correction codewords received, possibly corrupted by errors, attempts to
 * correct the errors in-place using Reed-Solomon error correction.</p>
 *
 * @param codewordBytes data and error correction codewords
 * @param numDataCodewords number of codewords that are data bytes
 * @throws ChecksumException if error correction fails
 */
private void correctErrors(byte[] codewordBytes, int numDataCodewords) throws ChecksumException {
  int numCodewords = codewordBytes.length;
  // First read into an array of ints
  int[] codewordsInts = new int[numCodewords];
  for (int i = 0; i < numCodewords; i++) {
    codewordsInts[i] = codewordBytes[i] & 0xFF;
  }
  int numECCodewords = codewordBytes.length - numDataCodewords;
  try {
    rsDecoder.decode(codewordsInts, numECCodewords);
  } catch (ReedSolomonException ignored) {
    throw ChecksumException.getChecksumInstance();
  }
  // Copy back into array of bytes -- only need to worry about the bytes that were data
  // We don't care about errors in the error-correction codewords
  for (int i = 0; i < numDataCodewords; i++) {
    codewordBytes[i] = (byte) codewordsInts[i];
  }
}
 

private static Result[] decode(BinaryBitmap image, Map<DecodeHintType, ?> hints, boolean multiple) 
    throws NotFoundException, FormatException, ChecksumException {
  List<Result> results = new ArrayList<>();
  PDF417DetectorResult detectorResult = Detector.detect(image, hints, multiple);
  for (ResultPoint[] points : detectorResult.getPoints()) {
    DecoderResult decoderResult = PDF417ScanningDecoder.decode(detectorResult.getBits(), points[4], points[5],
        points[6], points[7], getMinCodewordWidth(points), getMaxCodewordWidth(points));
    Result result = new Result(decoderResult.getText(), decoderResult.getRawBytes(), points, BarcodeFormat.PDF_417);
    result.putMetadata(ResultMetadataType.ERROR_CORRECTION_LEVEL, decoderResult.getECLevel());
    PDF417ResultMetadata pdf417ResultMetadata = (PDF417ResultMetadata) decoderResult.getOther();
    if (pdf417ResultMetadata != null) {
      result.putMetadata(ResultMetadataType.PDF417_EXTRA_METADATA, pdf417ResultMetadata);
    }
    results.add(result);
  }
  return results.toArray(new Result[results.size()]);
}
 

private int[] findErrorLocations(ModulusPoly errorLocator) throws ChecksumException {
  // This is a direct application of Chien's search
  int numErrors = errorLocator.getDegree();
  int[] result = new int[numErrors];
  int e = 0;
  for (int i = 1; i < field.getSize() && e < numErrors; i++) {
    if (errorLocator.evaluateAt(i) == 0) {
      result[e] = field.inverse(i);
      e++;
    }
  }
  if (e != numErrors) {
    throw ChecksumException.getChecksumInstance();
  }
  return result;
}
 

private static DecoderResult decodeCodewords(int[] codewords, int ecLevel, int[] erasures) throws FormatException,
    ChecksumException {
  if (codewords.length == 0) {
    throw FormatException.getFormatInstance();
  }

  int numECCodewords = 1 << (ecLevel + 1);
  int correctedErrorsCount = correctErrors(codewords, erasures, numECCodewords);
  verifyCodewordCount(codewords, numECCodewords);

  // Decode the codewords
  DecoderResult decoderResult = DecodedBitStreamParser.decode(codewords, String.valueOf(ecLevel));
  decoderResult.setErrorsCorrected(correctedErrorsCount);
  decoderResult.setErasures(erasures.length);
  return decoderResult;
}
 

/**
 * <p>Given data and error-correction codewords received, possibly corrupted by errors, attempts to
 * correct the errors in-place using Reed-Solomon error correction.</p>
 *
 * @param codewordBytes data and error correction codewords
 * @param numDataCodewords number of codewords that are data bytes
 * @throws ChecksumException if error correction fails
 */
private void correctErrors(byte[] codewordBytes, int numDataCodewords) throws ChecksumException {
  int numCodewords = codewordBytes.length;
  // First read into an array of ints
  int[] codewordsInts = new int[numCodewords];
  for (int i = 0; i < numCodewords; i++) {
    codewordsInts[i] = codewordBytes[i] & 0xFF;
  }
  try {
    rsDecoder.decode(codewordsInts, codewordBytes.length - numDataCodewords);
  } catch (ReedSolomonException ignored) {
    throw ChecksumException.getChecksumInstance();
  }
  // Copy back into array of bytes -- only need to worry about the bytes that were data
  // We don't care about errors in the error-correction codewords
  for (int i = 0; i < numDataCodewords; i++) {
    codewordBytes[i] = (byte) codewordsInts[i];
  }
}
 

@Override
public Result decode(BinaryBitmap image, Map<DecodeHintType,?> hints)
    throws NotFoundException, ChecksumException, FormatException {
  DecoderResult decoderResult;
  if (hints != null && hints.containsKey(DecodeHintType.PURE_BARCODE)) {
    BitMatrix bits = extractPureBits(image.getBlackMatrix());
    decoderResult = decoder.decode(bits, hints);
  } else {
    throw NotFoundException.getNotFoundInstance();
  }

  ResultPoint[] points = NO_POINTS;
  Result result = new Result(decoderResult.getText(), decoderResult.getRawBytes(), points, BarcodeFormat.MAXICODE);

  String ecLevel = decoderResult.getECLevel();
  if (ecLevel != null) {
    result.putMetadata(ResultMetadataType.ERROR_CORRECTION_LEVEL, ecLevel);
  }
  return result;
}
 

@Override
public Result decode(BinaryBitmap image, Map<DecodeHintType,?> hints)
    throws NotFoundException, ChecksumException, FormatException {
  DecoderResult decoderResult;
  if (hints != null && hints.containsKey(DecodeHintType.PURE_BARCODE)) {
    BitMatrix bits = extractPureBits(image.getBlackMatrix());
    decoderResult = decoder.decode(bits, hints);
  } else {
    throw NotFoundException.getNotFoundInstance();
  }

  ResultPoint[] points = NO_POINTS;
  Result result = new Result(decoderResult.getText(), decoderResult.getRawBytes(), points, BarcodeFormat.MAXICODE);

  String ecLevel = decoderResult.getECLevel();
  if (ecLevel != null) {
    result.putMetadata(ResultMetadataType.ERROR_CORRECTION_LEVEL, ecLevel);
  }
  return result;
}
 

/**
 * <p>Given data and error-correction codewords received, possibly corrupted by errors, attempts to
 * correct the errors in-place using Reed-Solomon error correction.</p>
 *
 * @param codewordBytes data and error correction codewords
 * @param numDataCodewords number of codewords that are data bytes
 * @throws ChecksumException if error correction fails
 */
private void correctErrors(byte[] codewordBytes, int numDataCodewords) throws ChecksumException {
  int numCodewords = codewordBytes.length;
  // First read into an array of ints
  int[] codewordsInts = new int[numCodewords];
  for (int i = 0; i < numCodewords; i++) {
    codewordsInts[i] = codewordBytes[i] & 0xFF;
  }
  try {
    rsDecoder.decode(codewordsInts, codewordBytes.length - numDataCodewords);
  } catch (ReedSolomonException ignored) {
    throw ChecksumException.getChecksumInstance();
  }
  // Copy back into array of bytes -- only need to worry about the bytes that were data
  // We don't care about errors in the error-correction codewords
  for (int i = 0; i < numDataCodewords; i++) {
    codewordBytes[i] = (byte) codewordsInts[i];
  }
}
 

@Override
public Result decode(BinaryBitmap image, Map<DecodeHintType,?> hints) throws NotFoundException, FormatException,
    ChecksumException {
  Result[] result = decode(image, hints, false);
  if (result == null || result.length == 0 || result[0] == null) {
    throw NotFoundException.getNotFoundInstance();
  }
  return result[0];
}
 

@Override
public Result[] decodeMultiple(BinaryBitmap image, Map<DecodeHintType,?> hints) throws NotFoundException {
  try {
    return decode(image, hints, true);
  } catch (FormatException | ChecksumException ignored) {
    throw NotFoundException.getNotFoundInstance();
  }
}
 

/**
 * <p>Convenience method that can decode a Data Matrix Code represented as a 2D array of booleans.
 * "true" is taken to mean a black module.</p>
 *
 * @param image booleans representing white/black Data Matrix Code modules
 * @return text and bytes encoded within the Data Matrix Code
 * @throws FormatException if the Data Matrix Code cannot be decoded
 * @throws ChecksumException if error correction fails
 */
public DecoderResult decode(boolean[][] image) throws FormatException, ChecksumException {
  int dimension = image.length;
  BitMatrix bits = new BitMatrix(dimension);
  for (int i = 0; i < dimension; i++) {
    for (int j = 0; j < dimension; j++) {
      if (image[i][j]) {
        bits.set(j, i);
      }
    }
  }
  return decode(bits);
}
 

@Override
public final Result decode(BinaryBitmap image, Map<DecodeHintType,?> hints)
    throws NotFoundException, ChecksumException, FormatException {
  DecoderResult decoderResult;
  ResultPoint[] points;
  if (hints != null && hints.containsKey(DecodeHintType.PURE_BARCODE)) {
    BitMatrix bits = extractPureBits(image.getBlackMatrix());
    decoderResult = decoder.decode(bits, hints);
    points = NO_POINTS;
  } else {
    DetectorResult detectorResult = new Detector(image.getBlackMatrix()).detect(hints);
    decoderResult = decoder.decode(detectorResult.getBits(), hints);
    points = detectorResult.getPoints();
  }

  // If the code was mirrored: swap the bottom-left and the top-right points.
  if (decoderResult.getOther() instanceof QRCodeDecoderMetaData) {
    ((QRCodeDecoderMetaData) decoderResult.getOther()).applyMirroredCorrection(points);
  }

  Result result = new Result(decoderResult.getText(), decoderResult.getRawBytes(), points, BarcodeFormat.QR_CODE);
  List<byte[]> byteSegments = decoderResult.getByteSegments();
  if (byteSegments != null) {
    result.putMetadata(ResultMetadataType.BYTE_SEGMENTS, byteSegments);
  }
  String ecLevel = decoderResult.getECLevel();
  if (ecLevel != null) {
    result.putMetadata(ResultMetadataType.ERROR_CORRECTION_LEVEL, ecLevel);
  }
  if (decoderResult.hasStructuredAppend()) {
    result.putMetadata(ResultMetadataType.STRUCTURED_APPEND_SEQUENCE,
                       decoderResult.getStructuredAppendSequenceNumber());
    result.putMetadata(ResultMetadataType.STRUCTURED_APPEND_PARITY,
                       decoderResult.getStructuredAppendParity());
  }
  return result;
}
 

@Override
public Result[] decodeMultiple(BinaryBitmap image, Map<DecodeHintType,?> hints) throws NotFoundException {
  try {
    return decode(image, hints, true);
  } catch (FormatException | ChecksumException ignored) {
    throw NotFoundException.getNotFoundInstance();
  }
}
 

public Result[] zxing( Mat inputImage ) throws ChecksumException, FormatException {

        int w = inputImage.width();
        int h = inputImage.height();

        Mat southEast;

        if (mBugRotate) {
            southEast = inputImage.submat(h-h/4 , h , 0 , w/2 - h/4 );
        } else {
            southEast = inputImage.submat(0, h / 4, w / 2 + h / 4, w);
        }

        Bitmap bMap = Bitmap.createBitmap(southEast.width(), southEast.height(), Bitmap.Config.ARGB_8888);
        org.opencv.android.Utils.matToBitmap(southEast, bMap);
        southEast.release();
        int[] intArray = new int[bMap.getWidth()*bMap.getHeight()];
        //copy pixel data from the Bitmap into the 'intArray' array
        bMap.getPixels(intArray, 0, bMap.getWidth(), 0, 0, bMap.getWidth(), bMap.getHeight());

        LuminanceSource source = new RGBLuminanceSource(bMap.getWidth(), bMap.getHeight(),intArray);

        BinaryBitmap bitmap = new BinaryBitmap(new HybridBinarizer(source));

        Result[] results = {};
        try {
            results = qrCodeMultiReader.decodeMultiple(bitmap);
        }
        catch (NotFoundException ignored) {
        }
        return results;
    }
 

private void onScanImageResult(Intent intent) {
    Uri inputFile = (intent.getData());
    Bitmap bitmap;

    try {
        BitmapFactory.Options bmOptions = new BitmapFactory.Options();

        try (InputStream inputStream = getContentResolver().openInputStream(inputFile)) {
            bitmap = BitmapFactory.decodeStream(inputStream, null, bmOptions);
        }

        int[] intArray = new int[bitmap.getWidth() * bitmap.getHeight()];
        bitmap.getPixels(intArray, 0, bitmap.getWidth(), 0, 0, bitmap.getWidth(), bitmap.getHeight());

        LuminanceSource source = new RGBLuminanceSource(bitmap.getWidth(), bitmap.getHeight(), intArray);
        BinaryBitmap binaryBitmap = new BinaryBitmap(new HybridBinarizer(source));

        Reader reader = new MultiFormatReader();
        Result result = reader.decode(binaryBitmap);

        GoogleAuthInfo info = GoogleAuthInfo.parseUri(result.getText());
        VaultEntry entry = new VaultEntry(info);

        startEditEntryActivity(CODE_ADD_ENTRY, entry, true);
    } catch (NotFoundException | IOException | ChecksumException | FormatException | GoogleAuthInfoException e) {
        e.printStackTrace();
        Dialogs.showErrorDialog(this, R.string.unable_to_read_qrcode, e);
    }
}
 

@Override
public final Result decode(BinaryBitmap image, Map<DecodeHintType,?> hints)
    throws NotFoundException, ChecksumException, FormatException {
  DecoderResult decoderResult;
  ResultPoint[] points;
  if (hints != null && hints.containsKey(DecodeHintType.PURE_BARCODE)) {
    BitMatrix bits = extractPureBits(image.getBlackMatrix());
    decoderResult = decoder.decode(bits, hints);
    points = NO_POINTS;
  } else {
    DetectorResult detectorResult = new Detector(image.getBlackMatrix()).detect(hints);
    decoderResult = decoder.decode(detectorResult.getBits(), hints);
    points = detectorResult.getPoints();
  }

  // If the code was mirrored: swap the bottom-left and the top-right points.
  if (decoderResult.getOther() instanceof QRCodeDecoderMetaData) {
    ((QRCodeDecoderMetaData) decoderResult.getOther()).applyMirroredCorrection(points);
  }

  Result result = new Result(decoderResult.getText(), decoderResult.getRawBytes(), points, BarcodeFormat.QR_CODE);
  List<byte[]> byteSegments = decoderResult.getByteSegments();
  if (byteSegments != null) {
    result.putMetadata(ResultMetadataType.BYTE_SEGMENTS, byteSegments);
  }
  String ecLevel = decoderResult.getECLevel();
  if (ecLevel != null) {
    result.putMetadata(ResultMetadataType.ERROR_CORRECTION_LEVEL, ecLevel);
  }
  if (decoderResult.hasStructuredAppend()) {
    result.putMetadata(ResultMetadataType.STRUCTURED_APPEND_SEQUENCE,
                       decoderResult.getStructuredAppendSequenceNumber());
    result.putMetadata(ResultMetadataType.STRUCTURED_APPEND_PARITY,
                       decoderResult.getStructuredAppendParity());
  }
  return result;
}
 

@Override
public Result decodeRow(int rowNumber,
                        BitArray row,
                        int[] startGuardRange,
                        Map<DecodeHintType,?> hints)
    throws NotFoundException, FormatException, ChecksumException {
  return maybeReturnResult(ean13Reader.decodeRow(rowNumber, row, startGuardRange, hints));
}
 

private static void checkOneChecksum(CharSequence result, int checkPosition, int weightMax)
    throws ChecksumException {
  int weight = 1;
  int total = 0;
  for (int i = checkPosition - 1; i >= 0; i--) {
    total += weight * ALPHABET_STRING.indexOf(result.charAt(i));
    if (++weight > weightMax) {
      weight = 1;
    }
  }
  if (result.charAt(checkPosition) != ALPHABET[total % 47]) {
    throw ChecksumException.getChecksumInstance();
  }
}
 

public DecoderResult decode(BitMatrix bits,
                            Map<DecodeHintType,?> hints) throws FormatException, ChecksumException {
  BitMatrixParser parser = new BitMatrixParser(bits);
  byte[] codewords = parser.readCodewords();

  correctErrors(codewords, 0, 10, 10, ALL);
  int mode = codewords[0] & 0x0F;
  byte[] datawords;
  switch (mode) {
    case 2:
    case 3:
    case 4:
      correctErrors(codewords, 20, 84, 40, EVEN);
      correctErrors(codewords, 20, 84, 40, ODD);
      datawords = new byte[94];
      break;
    case 5:
      correctErrors(codewords, 20, 68, 56, EVEN);
      correctErrors(codewords, 20, 68, 56, ODD);
      datawords = new byte[78];
      break;
    default:
      throw FormatException.getFormatInstance();
  }

  System.arraycopy(codewords, 0, datawords, 0, 10);
  System.arraycopy(codewords, 20, datawords, 10, datawords.length - 10);

  return DecodedBitStreamParser.decode(datawords, mode);
}
 

private static DecoderResult createDecoderResult(DetectionResult detectionResult) throws FormatException,
    ChecksumException, NotFoundException {
  BarcodeValue[][] barcodeMatrix = createBarcodeMatrix(detectionResult);
  adjustCodewordCount(detectionResult, barcodeMatrix);
  Collection<Integer> erasures = new ArrayList<>();
  int[] codewords = new int[detectionResult.getBarcodeRowCount() * detectionResult.getBarcodeColumnCount()];
  List<int[]> ambiguousIndexValuesList = new ArrayList<>();
  List<Integer> ambiguousIndexesList = new ArrayList<>();
  for (int row = 0; row < detectionResult.getBarcodeRowCount(); row++) {
    for (int column = 0; column < detectionResult.getBarcodeColumnCount(); column++) {
      int[] values = barcodeMatrix[row][column + 1].getValue();
      int codewordIndex = row * detectionResult.getBarcodeColumnCount() + column;
      if (values.length == 0) {
        erasures.add(codewordIndex);
      } else if (values.length == 1) {
        codewords[codewordIndex] = values[0];
      } else {
        ambiguousIndexesList.add(codewordIndex);
        ambiguousIndexValuesList.add(values);
      }
    }
  }
  int[][] ambiguousIndexValues = new int[ambiguousIndexValuesList.size()][];
  for (int i = 0; i < ambiguousIndexValues.length; i++) {
    ambiguousIndexValues[i] = ambiguousIndexValuesList.get(i);
  }
  return createDecoderResultFromAmbiguousValues(detectionResult.getBarcodeECLevel(), codewords,
      PDF417Common.toIntArray(erasures), PDF417Common.toIntArray(ambiguousIndexesList), ambiguousIndexValues);
}
 

/**
 * <p>Decodes a Data Matrix Code represented as a {@link BitMatrix}. A 1 or "true" is taken
 * to mean a black module.</p>
 *
 * @param bits booleans representing white/black Data Matrix Code modules
 * @return text and bytes encoded within the Data Matrix Code
 * @throws FormatException if the Data Matrix Code cannot be decoded
 * @throws ChecksumException if error correction fails
 */
public DecoderResult decode(BitMatrix bits) throws FormatException, ChecksumException {

  // Construct a parser and read version, error-correction level
  BitMatrixParser parser = new BitMatrixParser(bits);
  Version version = parser.getVersion();

  // Read codewords
  byte[] codewords = parser.readCodewords();
  // Separate into data blocks
  DataBlock[] dataBlocks = DataBlock.getDataBlocks(codewords, version);

  int dataBlocksCount = dataBlocks.length;

  // Count total number of data bytes
  int totalBytes = 0;
  for (DataBlock db : dataBlocks) {
    totalBytes += db.getNumDataCodewords();
  }
  byte[] resultBytes = new byte[totalBytes];

  // Error-correct and copy data blocks together into a stream of bytes
  for (int j = 0; j < dataBlocksCount; j++) {
    DataBlock dataBlock = dataBlocks[j];
    byte[] codewordBytes = dataBlock.getCodewords();
    int numDataCodewords = dataBlock.getNumDataCodewords();
    correctErrors(codewordBytes, numDataCodewords);
    for (int i = 0; i < numDataCodewords; i++) {
      // De-interlace data blocks.
      resultBytes[i * dataBlocksCount + j] = codewordBytes[i];
    }
  }

  // Decode the contents of that stream of bytes
  return DecodedBitStreamParser.decode(resultBytes);
}
 

/**
 * This method deals with the fact, that the decoding process doesn't always yield a single most likely value. The
 * current error correction implementation doesn't deal with erasures very well, so it's better to provide a value
 * for these ambiguous codewords instead of treating it as an erasure. The problem is that we don't know which of
 * the ambiguous values to choose. We try decode using the first value, and if that fails, we use another of the
 * ambiguous values and try to decode again. This usually only happens on very hard to read and decode barcodes,
 * so decoding the normal barcodes is not affected by this. 
 *
 * @param erasureArray contains the indexes of erasures
 * @param ambiguousIndexes array with the indexes that have more than one most likely value
 * @param ambiguousIndexValues two dimensional array that contains the ambiguous values. The first dimension must
 * be the same length as the ambiguousIndexes array
 */
private static DecoderResult createDecoderResultFromAmbiguousValues(int ecLevel,
                                                                    int[] codewords,
                                                                    int[] erasureArray,
                                                                    int[] ambiguousIndexes,
                                                                    int[][] ambiguousIndexValues)
    throws FormatException, ChecksumException {
  int[] ambiguousIndexCount = new int[ambiguousIndexes.length];

  int tries = 100;
  while (tries-- > 0) {
    for (int i = 0; i < ambiguousIndexCount.length; i++) {
      codewords[ambiguousIndexes[i]] = ambiguousIndexValues[i][ambiguousIndexCount[i]];
    }
    try {
      return decodeCodewords(codewords, ecLevel, erasureArray);
    } catch (ChecksumException ignored) {
      //
    }
    if (ambiguousIndexCount.length == 0) {
      throw ChecksumException.getChecksumInstance();
    }
    for (int i = 0; i < ambiguousIndexCount.length; i++) {
      if (ambiguousIndexCount[i] < ambiguousIndexValues[i].length - 1) {
        ambiguousIndexCount[i]++;
        break;
      } else {
        ambiguousIndexCount[i] = 0;
        if (i == ambiguousIndexCount.length - 1) {
          throw ChecksumException.getChecksumInstance();
        }
      }
    }
  }
  throw ChecksumException.getChecksumInstance();
}